This invention relates to a chuck jaw assembly for a fastener setting apparatus. More particularly, this invention relates to an elastomeric connector for maintaining the jaw teeth of a chuck jaw assembly in a predetermined relationship with respect to each other.
Apparatus for setting fasteners are well known. In general, these devices have an outer body to receive a fastener and a chuck jaw assembly within the outer body for gripping and setting the fastener. Typical prior art devices are shown in U.S. Pat. No. 4,344,311 and No. 4,057,980. With such devices, problems arise in maintaining the jaw teeth that grip a fastener in proper axial and circumferential positions with respect to each other.
A prior art apparatus for setting fasteners is shown in U.S. Pat. No. 4,347,728 in which a chuck jaw assembly is disclosed that has a tubular elastomeric sleeve member disposed behind and connected to the fastener engaging jaw teeth to maintain the jaw teeth in predetermined positions with respect to each other. This arrangement is undesirable since large stresses will be placed on the connection between the sleeve member and the jaw teeth, which must flex radially inwardly and outwardly and return to a predetermined position. With repeated use of the apparatus, the jaw teeth may simply snap away from the sleeve member.
Another prior art device is shown in U.S. Pat. No. 4,598,572 in which the jaw teeth are received in pockets in an elastomeric tubular member. With this device, the jaw teeth have a rear portion that is ridged so that they are gripped within the pockets. These ridges require special machining increasing the cost of the jaw teeth. Further, as the jaw ieeth become worn with use they may tend to drift outwardly from the pockets. Also, the teeth are restrained to an undesirable extent since the pockets disclosed by this patent have a portion holding the jaw teeth that is radially inward from the jaw teeth inner diameter.
U.S. Pat. No. 3,595,593 discloses a collet for use in jaws that are maintained in proper axial alignment by O-rings. While an arrangement such as shown in this patent would have advantages over the prior art patents discussed above, some problems still remain. A complex arrangement of springs and spacers is utilized to maintain proper circumferential spacing. The arrangement is overly complex and still may not adequately maintain the desired circumferential spacing between the jaws and also may not be useful in an apparatus for setting fasteners.
A still further prior art apparatus for setting fasteners uses only an O-ring to hold the jaw teeth. The O-ring is received in a groove formed in the rear portion of the jaw teeth. This device lacks means for circumferentially spacing the jaw teeth.
U.S. Pat. No. 3,610,641 shows a drill chuck assembly that has a relatively complex apparatus for separating the chuck elements. This arrangement is complex and may not be useful in an apparatus for setting fasteners or for a jaw chuck assembly that must be capable of sliding.
It is therefore an object of the present invention to disclose a chuck jaw assembly for use in an apparatus for setting fasteners that will solve the problems faced by the prior art. More particularly, it is an object of the present invention to disclose a chuck jaw assembly with an elastomeric connector, or retaining member, that maintains the jaw teeth in predetermined axial and circumferentially spaced positions.